GB2320305A

GB2320305A - Circlip

Info

Publication number: GB2320305A
Application number: GB9725034A
Authority: GB
Inventors: Ferdinand Schweitzer
Original assignee: SKF GmbH
Current assignee: SKF GmbH
Priority date: 1996-12-10
Filing date: 1997-11-26
Publication date: 1998-06-17
Anticipated expiration: 2017-11-26
Also published as: DE19651176B4; DE19651176A1; SE9704447L; AT409889B; US6079897A; SE518737C2; ATA142197A; GB9725034D0; SE9704447D0; GB2320305B

Abstract

A circlip 6 is provided with a circumferential line of weakening to provide a preferred line of fracture when subjected to an axial force or impact, so as to permit release of the connected machine parts. The line of weakening may be provided by grooves 8 (Fig 3), or closely spaced holes 11 (Fig 4, not shown), or by interruptions 13 (Fig 5). Circlips 6 may be used to secure a roller bearing in a bore and onto a shaft (Fig 1, not shown).

Description

AXIAL LOCKING DEVICE 2320305

This invention relates to a releasable axial locking device for machine parts. Disclosed in DE 33 46 661 is a snap ring, which, apart from where it is slotted, does not provide any features for applying a fitting tool. Its bore and lateral area are cylindrical, which allows for using the snap ring in radial grooves in bores as well as lateral areas. It serves as axial locking device for machine parts and could also be used as a locking device for a shaft in a bore etc. In this application the radial grooves are that deep that there is space for the full radial height of the snap ring. In the first stage of the introduction of the shaft into the bore the snap ring springs into one radial groove and later on into the other. As the snap ring is no longer accessible from outside the known connection described hereinabove is regarded as unreleasable.

It is the object of at least the preferred embodiment of the invention to improve the known snap ring, so that releasing of the connection is possible without damaging the connected machine parts.

Accordingly, in one aspect the present invention comprises a snap ring for releasably, axially locking a machine part in a bore, the radially outer edge of the ring being adapted to be inserted in a circumferential groove of the bore and the radially inner portion of the ring being adapted to be inserted in a circumferential groove in the machine part, wherein the snap ring is weakened intermediate its radially inner and outer portion in a circumferential direction to provide a preferred line of fracture.

The invention also provides an assembly comprising a machine part locked in a bore by a snap ring as set forth above.

Preferred features are as set out in the subordinate claims which are deemed repeated here as consistory clauses.

In a specific embodiment the above-mentioned object can be achieved by weakening the material of the snap ring at the height of the bore diameter in circumferential direction and by designing the remaining material as a rated break point.

The snap ring according to the preferred embodiments can meet all operational 1 requirements. It withstands the maximum axial operational load that could arise, without getting damaged; in other words, the force necessary to break the snap ring is bigger than the maximum axial load. However, the force necessary to break the snap ring is smaller than the load that would damage the radial grooves, in particular the sides of the groove.

The weakening is achieved by various measures, however, it always runs in circumferential direction. For example, it is possible to build a ring groove into the sides or to provide sections with openings. All alternatives provide a weakening that runs around the perimeter, and which acts as a rated break point (preferred line of fracture) during dismantling.

When releasing the connection, a rupture along the ring grooves of the snap ring is caused by an axial force or impact in the axial direction between the shaft and the bore. After that, the shaft and both parts of the broken snap ring can be taken out of the bore. A new connection can be made by using a new snap ring.

The invention will now be described by way of example illustrated in the drawings.

Figure 1 shows the partial longitudinal section of a cylindrical roller bearing secured on a shaft and inside a bore by snap ri. Lngs; Figure 2 shows the side view of a snap ring according to Figure 1; Figure 3 shows the longitudinal section of the snap ring according to Figure 2 on line A-A; Figure 4 shows the side view of a snap ring with bores along the ring shaped preferred line of fracture; Figure 5 shows the side view of a snap ring with interruptions that are open in radial direction towards the inside; and Figure 6 shows the side view of a snap ring with interruptions that are open in radial direction towards the outside.

The cylindrical roller bearing shown in Figure 1 comprises radial grooves 3 in the circumferential area 1 of the outer ring and in the bore 2 of the inner ring. Corresponding radial grooves 3 are provided in the bore 4 of the structure in which the bearing is mounted and in the circumference of a shaft 5 carried by the bearing.

All radial grooves 3 have a rectangular profile and are adapted to the width of the snap rings 6 placed in these grooves. The depth of the radial grooves 3 in the bore 4 and in the shaft 5 corresponds to approximately half the radial height of the snap rings 6. The depth of the radial grooves 3 in the outer and inner ring corresponds to the whole radial height of the snap rings 6.

At one point of the perimeter of the snap rings 6 there is a slot 7. The snap ring 6 which is inserted in the outer ring according to Figure 1 is shown relaxed in Figures 2 and 3. It has expanded radially outwardly, and therefore the slot 7 is wider in this situation. At half the radial height V-shaped ring grooves are provided on both sides, which reduce the thickness of the material between the bottoms of the grooves, which serves as a ring-shaped preferred line of fracture 9.

In the relaxed position shown, the snap ring 6 is situated in the radial groove 3 of the outer ring even before the introduction of the cylindrical roller bearing into the bore 4.

When the cylindrical roller bearing is introduced the snap ring 6 is contracted radially. Its radial height is situated entirely within the radial groove 3 of the lateral area 1 of the outer ring. In this situation the slot according to Figure 2 is closed up. When reaching the radial groove 3 in the bore 4 of the cage the snap ring 6 relaxes into this radial groove 3 because of its residual stress and its lateral area would lay by the bottom of the groove. In this position half of the depth of the groove in the outer ring is empty and the V-shaped ring grooves 8 are aligned with the bore 4. In this position the cylindrical roller bearing is axially secured.

In order to release the axial locking device, the outer ring is separated from the bore 4 of the cage by application of an axial force or impact. The edges or sides of the radial grooves 3 act as a shearing tool and separate the snap ring 6 at the preferred line of fracture 9 between the two V-shaped ring grooves 8. The preferred line of fracture is designed in a way that the force needed to separate the snap ring 6 does not cause any damage at the radial grooves 3. The V-shaped sides 10 of the groove prevent any now unwanted closing-up of the separated snap ring 6 in the radial grooves 3 and provide sloping ramps for the sides of the radial grooves 3 so that the two halves of the snap ring 6 can easily be removed from the radial grooves 3.

The axial locking and dismantling at the inner ring can be performed in a - __1 similar way. In this case the snap ring 6 will not be contracted and therefore a slot as shown in Figure 2 is not necessary in the reset position.

In the embodiment shown in Figure 4 a further weakening is provided by holes 11 situated closely next to each other. lle remaining bridges 12 between the holes 11 are equipped with a radial groove 8 as described in Figure 1, 2 and 3. This reduces the force necessary to break the snap ring during dismantling considerably.

Furthermore, instead of holes 11 one could provide slots or other points of weakness in a ring shaped arrangement.

In the embodiment according to Figures 5 and 6, one half of the height of the snap ring situated in one of the two radial grooves has interruptions 13. Thus tongue shaped sections 14 remain, which in one aspect result in approximately half the perimeter for the axial locking, but in another aspect reduce the overall length of the preferred line of fracture 9. In order to reduce the force necessary to separate the snap ring, ring groove sections 8 are provided at the tongue shaped sections as well.

Of course, the present invention is not restricted to releasably, axially locking a roller bearing but can be applied to releasably, axially locking other structures.

Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.

The text of the abstract filed herewith is repeated here as part of the specification.

A snap ring 6, for example with V-shaped ring grooves 8 formed into its sides, is provided for axially locking machine parts. The ring grooves 8 are situated at the height of the connecting surfaces 1, 2, 4 and 5 of the machine parts and form a ring shaped preferred line of fracture 9 which is located therebetween. Thus the locking can be released by separating the snap ring at the preferred line of fracture 9.

Claims

1. A snap ring for releasably, axially locking a machine part in a bore, the radially outer edge of the ring being adapted to be inserted in a circumferential groove of the bore and the radially inner portion of the ring being adapted to be inserted in a circumferential groove in the machine part, wherein the snap ring is weakened intermediate its radially inner and outer portion in a circumferential direction to provide a preferred line of fracture.

2. A snap ring according to Claim 1, wherein the snap ring is weakened by a circular groove, which reduces the thickness of the ring, in at least one side.

3. A snap ring according to Claim 2, wherein said groove is of a V-shaped cross- section.

4. A snap ring according to Claim 2 or Claim 3, wherein a said groove is provided in both sides of the snap ring.

5. A snap ring according to any one of the preceding Claims wherein openings are angularly distributed around the ring.

6. A snap ring according to any one of the preceding Claims, wherein either the radially inner or outer edge of the ring comprises radially extending interruptions with tongue shaped sections therebetween.

7. An assembly of a machine part locked in a bore by a snap ring according to any of the preceding Claims, the preferred line of fracture being aligned with the interface between the machine part and the bore.

8. An assembly according to Claim 7, wherein the bore and the machine part have aligned circumferential grooves, one groove having a radial depth at least equal to the radial width of the snap ring, the other groove being of a lesser depth, the ring being elastically deformed such that resilience of the ring urges it into said other groove.

9. An assembly according to Claim 8, wherein the radial depth of the said other 1 groove is approximately half of the radial width of the snap ring.

10. An assembly according to any of Claims 7 to 9, wherein the machine part is a race of a rolling bearing.

11. A snap ring or an assembly substantially as described hereinabove with reference to the accompanying drawings.